m THE LAST HALE-CEXTUKY. 31 



The object is the discovery of the ra- the dis- 



d covery 



tional order which, pervades the universe ; of the 



-. rational 



the method consists of observation ana order of 

 experiment (which is observation under ve J s £ m " 

 artificial conditions) for the determination 

 of the facts of nature ; of inductive and 

 deductive reasoning for the discovery of 

 their mutual relations and connection. 

 The various branches of physical science 

 differ in the extent to which, at any given 

 moment of their history, observation on 

 the one hand, or ratiocination on the other, 

 is their more obvious feature, but in no 

 other way ; and nothing can be more in- 

 correct than the assumption one sometimes 

 meets with, that physics has one method, 

 chemistry another, and biology a third. 



All physical science starts from cer- it is 

 tain postulates. One of them is the ob- onpos- 

 jective existence of a material world. It 

 is assumed that the phenomena which are 

 comprehended under this name have a 

 'substratum' of extended, impenetrable, 



